1. Field of the Invention
This invention relates to a miniature electronic device having a calculating ability.
2. Description of the Prior Art
A conventional miniature type electronic device having a calculating ability makes use of an electric source switch which is selectively turned ON and OFF so as to change over a calculation enable mode to a calculation disable mode and vice versa. In the calculation disable mode, an electric source is disconnected from a calculation circuit, so that the contents of the registers constituting the calculation circuit are lost. As a result, when the electric source switch is turned ON so as to obtain the calculation enable mode, entirely meaningless numbers are displayed or a calculation circuit is automatically cleared thus is displayed zero.
Such conventional device is very inconvenient when calculation keys are operated at intervals of time which are separated from each other. For example, in the case of leaving sums of money paid during daytime as they are and calculating the final result thereof at night, the electric source switch is required to be the ON position for a long time in order to keep the calculation result until a next input arrives at the calculation circuit, thereby consuming a large amount of electric power. In addition, careful attention must be paid not to change the calculation result by touching the calculation key by mistake between calculation periods.